1. Field of the Invention
The invention relates to the field of chemical treatment of workpiece surfaces, for example, acidic etching of metal workpiece surfaces.
2. Description of Prior Art
High speed plating systems for metallic workpieces such as cylinders of internal combustion engines using automated handling equipment for the workpieces involves acidic etching of the cylinder bores in a high speed process wherein circulation of mixed acid etchant through the cylinder bore is used to etch the surface of the bore in preparation for a plating operation.
However, during the etching process, harmful gases such as oxides of nitrogen (NO.sub.x) are produced and must be disposed of for safety and environmental reasons. In accordance with prior art solutions, separate handling systems for the dangerous and undesirable gaseous byproduct of the etching process must be provided, including appropriate conduits, pumps and other apparatus for safely conducting the gaseous byproduct away from the etching area to a disposal or recovery system. Such systems tend to be complex, costly and disadvantageous with respect to equipment layout.
Thus, the problem to be solved by the present invention is to eliminate the need to establish special apparatus to transport and deal with harmful gases produced during a chemical treatment process by recovering and eliminating the gases in a way to minimize costs and complexity of equipment layout.